Military exercises among treaty allies should normally neither surprise nor cause offence. But those just completed between the United States and the Philippines are being perceived differently, and not without some justification.

With some 7,000 troops reportedly involved, the bilateral exercise took place around Palawan in the South China Sea, where different islets are disputed between China and the Philippines. Moreover, the exercise followed a high-profile stand-off between the Philippine coast guard and fishing vessels from China at the disputed Scarborough Shoal.

Military commanders on both sides mostly treated the exercise as routine, part of the long-running Balikatan manoeuvres. Political statements run contrary to this. Both Philippine President Benigno Aquino and Foreign Secretary Albert del Rosario reacted by calling on not only the United States but also other members of Asean to rally against China's alleged aggressiveness.

Beijing, in contrast, has shown restraint. While its media commentators have been hawkish, government officials like Vice-Foreign Minister Cui Tiankai have emphasised dialogue and diplomacy. Privately, officials admit that a historical map they released with dotted lines all across the South China Sea does not mean they claim it all.

A public retraction by Beijing would, however, be almost impossible at this time of leadership change and internal turbulence. Following Bo Xilai's high-profile dismissal, questions are being asked about the military's alignment and nationalistic drum-beating would be a tempting response that the Chinese leaders have so far not given in to.

So, how best should the Americans and the Association of Southeast Asian Nations respond? The Obama administration's declaration of a 'pivot' to Asia sets the context. Many read this to mean that the US is prepared to take sides against China, even as American leaders strongly deny any such intention.

Symbolism must be watched. At the end of last year, US Secretary of State Hillary Rodham Clinton celebrated the 60th anniversary of their Filipino alliance aboard a US guided missile destroyer in Manila Bay. She also pledged to support the Philippines in the maritime domain and transfer a naval vessel to their command.

The reality is that the Americans face a reduction in their forces across Asia. The US military have recently reduced its presence in Okinawa by 9,000 marines. The Philippines, which once hosted large American military contingents at the Subic and Clark bases, has now welcomed American troops to return, on a rotational basis, although there is currently no suggestion for new bases.

The current Obama team is savvy enough to manage the pivot to Asia without getting ensnared in anti-Chinese interests. But even if President Barack Obama is re-elected, Clinton has indicated she will leave and their well-regarded point man on Asia, Assistant Secretary of State Kurt Campbell, is also likely to depart.

Thus, a new American team will be in place by next year and there will be a learning curve. If it is a Republican administration in the White House, tensions could rise, given the strong campaign rhetoric from leading contender Mitt Romney.

For its part, Asean should not automatically back the Philippines. Nor should the Aquino government expect unquestioning support from the group if the Filipinos seem to be the ones who are provoking the issue, rather than the Chinese.

Asean needs to reinforce the multilateral setting for dialogue about the South China Sea and other issues. The Asean Regional Forum will be one venue, while another will be when Asean defence ministers meet eight counterparts, including those from the US and China. More specifically, a code of conduct for disputes in the South China Sea has been promised, and needs to be fleshed out and agreed on in practical terms.

Bilateral security alliances - like that between the US and the Philippines - were once accepted as a foundation for Pax Americana. They will undoubtedly continue. Moreover, some appear anxious to reinforce them by, if necessary, ringing the China alarm bells.

Today's need, however, is not for more aggressive alliances with the US, targeted against anyone. The region needs instead to pursue and strengthen wider processes that can engage both the US and China.

Almost all agree that keeping the Americans in Asia can be positive. But, equally, the region must understand that treating Beijing as an outsider and presuming it to always be the aggressor is a dangerous, and potentially self-fulfilling, prophecy.

Simon Tay is chairman of the Singapore Institute of International Affairs and author of Asia Alone: The Dangerous Post Crisis Divide from America. He also teaches international law at the National University of Singapore. This article first appeared in Singapore's Today newspaper